Shock absorbing device



July 18, 1933. R. L .GRuss SHOCK BSORBING DEVICE Filed Oct. 22. 1928 INVENTOR l ATTORNEYS Patented `luly 18, 1933 UNITED STATES PATENT oEFicE aAYnoND I.. Gauss, or sAN FRANCISCO, CALIFORNIA; LAURA E. amiss, ADMINIS- raa'rmx or san) RAYMOND I.. Gauss, nECEssnn, AssIaNoa,v BY mEsNn AssIGN;

SHOCK ABSORBING DEVICE Application nled October 22, 1928. Serial No. 318,986. Y

v M present invention relates to pneumatic shoc absorbing devices and more particularly to a device of this character suitable for use in connection with the landing gear of aero lanes.

An o ject of my invention is to provide a novel arrangement of pneumatic shock abv sorbing devices in connection with the landing gear of aeroplanes. v Another object of my invention is to provide a novel type of pneumatic shock absorbing device which can be mounted in the position of a strut in applying the invention to the landing gear of an aeroplane.

A further object of my invention is to provide in combination with a pneumatic air cushion device, means for checking rebound whichv will ermit of an extension of the shock absor ing device when the landing gear is out of contact with the earth.

For a better -understanding of my invention, reference should be had to the accompanyin drawing, wherein I .have shown by way o illustration and not of limitation one manner of vattaching my improved device and also the internal construction of a referred modification of same.

n this drawing- Figurel is a ront view in elevation of 80 an aero lane equipped with my improved shock a orbing device,

I of -Figure 3 is a view similar to that of Fig- 85 ure 2 showing the parts in their collapsed position. y In Figure 1, 10 designates the viuselagz i having a wing structure 11 of the monoplanetype. e wing structure 11 is supported upon the fuselage 10 by means of suitable struts 12 and 13 and connected-to the fuse-v a'ge at its central. point I show a wheel axle 14 whichis in two parts, each part being -j hinged at its inner end to the fuselage'. Mounted vupen the axles 14 are the 4usual landing wheels 15. and vinterposed between the axles l4`adjacent the wheels 15, I ropose to mount my improved shock absor ing `device or strut which I have designated by othe numeral 16. The struts 16 are secured to l shown.

Figure 2 is a longitudinal sectional viewmy device in its extended condition, and

and is vguided therein ence of the air pressure therein, extend itself so that the wheels will assume a position further removed from the plane than here This will permit the wheels to establish contact with the ground in landin before the weight of the lane is assum' thereby and, as a result, t e weight of the plane will be slowly taken up by the air cushion as will hereinafter ap ear and thus the iirstshock and impact o landing will be absorbed by the full len h of the air cushion, the pressure within t e pneumatic c linder `starting at a low value and gradua ly increasing as the strut is compressed,there by -checking the downward motion of the p ane in direct proportion to the force at which a landing is made.

The further aspect of my invention with respect to the rebound reventing characteristics thereof will best e understood in connection with -a descri tion of Figures 2 and 3. In these Figuresog the drawing it will be v seen that the s hock absorbin 16y is comprised of an inverted neumatic cylinder 20 and a piston head 21 apted to operate therein when pressure is brought to bear thereupon by reason of external forces.- The device or strut piston head 21 in this embodimentof my invention is shown as Erovided with a cylindrical portion 22 whic extends out of thel cylinder 2O and a rod 23 havin an enlar ed head` 24-which also projects ouwardly grom the pistony head and centrally of the cylindrical portion 22. Cooperating with the cylindrical e5 portion 22 and the enlarged head 24 I also v provide a second cylindrical rtion or hydraulic cylinder 25 which is a a ted to move ,vertically within the cylindrica portion 22 y means of annular 10o mined by the fluidity of the liquid contained therein and the clearances for the flow of liquid between its walls and the enlarged head 24. In this connection it might be said that the enlarged head may, where desired, be provided with additional by-pass ports 28 for the purpose of increasing the iow of oil about the head 24 so that various rates of movement may be obtained. This feature, of course, can

be modified in many respects: for instance,'

the enlarged head 24 may be made to have a rather close fit within the cylinder 25 and the by-pass of oil controlled through interior ports; or the head might be made relatively small so that all of the liquid flowing thereabout will pass around the outside thereof. The piston head 21 is shown as provided with an upstanding-packing gland 29 and immediately thereabove within the pneumatic cylinder 20 I have shown a quantity of oil 30. The function of this oil is to lubricate the interior of the cylinder 20 and to act as a seal in combination with the gland 29 against the escape of the air from the cylinder 20. At the top of the cylinder 2O I provide a suitable air inlet and valve mechanism 31, the valve in this case being of the ordinary pneumatic tire type and adjacent thereto is a second plug 32 through which the oil is introduced into the cylinder. Atthe uppermost end of the cylinder and projecting vertically therefrom I form a pair of ears 33 ywhich are adapted to be pivotally connected upon a suitable part of the aero lane fuselage or struts. The lower end of t e cylinder 2O is closed by a screw threaded annular plug 34 and a slight distance thereabove a second and similar plug 35 is provided which limits the downward movement of the piston head 20. In order to insure against the loss of oil at this point where the cylindrical portion 22 projects out of the cylinder 20 I provide between the annular plugs 34 and 35 a plurality of packing rings 36. These rings 36 are of standard design and have suit-able spreaders and a spring 37 which tends to hold them in their expanded position.

At the lower end of the cylindrical portion 22 I provide an annular ring or nut 38 which serves as a closure member therefor and also limits the downward movement of the hydraulic cylinder 25. The lower end of the cylinder 25 carries a second pair of ears 39 similar to the ears 33 by means of which the lower end of my shock absorbing device 16 is secured to the axle 14 ofthe landing gear. In connection with the ears 33 and 39 it might be pointed out thatinstead Aof a pair of ears a single such member might be used. This will depend upon the nature of the cooperating coupling device or support.

The operation of my im roved shock absorbing strut is as follows: t will be assumed that the cylinder 2O has been pumped up with air to a. suitable pressure and that the plane to which it is attached is in the air and about to make a landing. Under these conditions the parts of my improved device will have assumed the positions in which they are illustrated in Figure 2 of the drawing. From this figure of the drawing it will be seen that the piston head 21 is in its lowermost position within the cylinder 20 with the cylindrical portion 22l projecting out of the cylinder 20. It will also be seen that the hydraulic cylinder 25 has assumed its lowermost or extended position. The position of the cylinder head 21 and-its cylindrical portion 22 is occasioned by the pressure of the air within the cylinder 20 acting upon the piston head 21 and the position of the hydraulic cylinder 25 is the result of the weight of the under carriage structure and particularly the axle 14 and wheels 15. The oil or other liquid within the' hydraulic cylinder 25 will have, as shown, assumed a position in the lowermost part of the cylinder and will extend substantially to the level illustrated in this figure of the drawing. When the wheels 15 of the aeroplane contact with the ground in landing, the first impact caused thereby will be taken up by the full length of deiection of the air as determined by the force of the impact and the pressure of the air maintained within the cylinder 20. After the wheels are in permanent contact with the ground, the air cushion will gradually pick up the weight of the machine and at the same time the hydraulic cylinder 25 will tend to slowly move u wardly over the enlarged head 24 carried y the rod 23 so that in the event that the wheels leave the ground during landing either due to sudden impact or uneven ground, the tendency to rebound will be checked hydraulically.

After the weight of the plane has been transferred to the wheels 15, the parts of my improved device will assume the position substantially as shown in Figure 3. When the parts are in this position, it will be seen that the piston head has moved upwardly within the cylinder 20 a distance depending upon the amount of pressure carried within the cylinder. It will also be seen that the hydraulic cylinder 25 has telescoped within the cylindrical portion 22 and that the oil therein has been displaced so that it now lies mostly above the enlarged head 24 carried b the rod 23. This figure of the drawing also illustrates the position of the parts during the taxiing period of the plane. From an inspection of this figure of the drawing it will be seen that the entire weight of the plane will be supported upon cushions of compressed air and that as the plane rises from the ground the air pressure within the Y the cylinder 20 to expand an cylinder will extend m devicein proportion to the wei ht remove from the wheels and thus estab ish a condition whereinfthe greatest amount of flexibility under that weight will be automatically produced, thus relieving the plane of all jar and rack when taxiing over rough ground. In taking o, as the plane tends to rise, the device will extend itself and thus allow the com ressed air in thus o erate to su port a portion of the load until the whee s finally leave the ground. At this time the hydraulic cylinder 25 will tend to slowl extend itself with respect to the c linl5 drica ortion 22 as determined by the c earances therebetween the cylinder 25 and the enlar ed head 24, and should it happen that the w eels again contact with the ground the. air cushion within the cylinder 2O wil be immediately brought into lay without necessitatin a loss of altitude y the plane. The flow o liquid within the cylinder will, as previously stated check the tendencies to any rebound and will also prevent a sudden ex- 25 tension of the shock absorbing device without detracting from the eiliciency of the air cushion.

I have found that my device makes it possible to effect a much more rapid take-oli and shorter landings. These characteristics I attribute particularl to the fact that the air cushion, once thewlieels touch the ground, gradually amumes the wei ht of the machine, while at the same time the ydraulic cylinder permits the machine to settle with the wheels always in contact .with the ground during this period and also the fact that the possibilities of rebound are substantially eliminate 40 Y From the above, it will be seen that I have produced a new and improved type ofshock `absorbing device for aeroplanes and the like and while I have shown in the accompanying drawing a preferred embodiment thereof I desire to have it understood that many modifications thereof will readily/ suggest themselves to those skilled in the art to which my invention appertains without departing from the spirit and sco of the invention as 5 defined in the append claims.

y Having thus escribed my invention, what I claim and desire to secure by Letters Patent is 1. A shock absorbing device for aeroplanes comprising a pneumatic cylinder, a piston movable therein, a tubular extension carried by the piston and projecting from the end of the pneumatic cylinder, a hydraulic cylinder telescoping with the tubular'extens'ion and G0 containing an incompressible Huid, and means movable with said tubular extension and working in said incompressible fluid for transmitting the movements of one of said c linders to the other whereby movement of the penumaticcylinder and the hydraulicv the piston and cylinder with relation to each other in landing and taking ofi' will be accompanied by a di erent movement of the iston with relation to the pneumatic c lin er. 4

2. A shock absorber or aeroplane landing gears comprising a penumatic cylinder, a piston therein, aV tubular extension carried by extending from the mouth of the pneumatic cylinder, a hydraulic cylinder telescoping within the tubular extension and containing an incompressible fluid, a piston rod carried by the piston and extending longitudinally of the tubular extension and in to the hydraulic cylinder, and means carried by the piston rod and at all times submerged within the incompressible fluid of the hydraulic cylinder to cause movement of the piston in a diierent degree and rate of speed as the pneumatic cylinder and the hydraulic cylinder move with relation to each other.

3. A shock absorbing device for aeroplane landing gears comprising a pneumatic cylinder, a piston reciprocable therein, a cylindrical extension carried by the piston and projectin from the mouth of the pneumatic c lindger, a hydraulic cylinder fitting Within t e 'cylindrical extension and being free to telescope with relation thereto, said cylinder enclosing an incompressible iluid, a piston rod secured to the iston and extendin longitudinally into the hydraulic cylin er, a piston head carried at the end of said rod and at all times submerged in the incompressible fluid, and means incorporated in said head for permitting a metered flow of incom ressible fluid amount the head, whereby orce tending to move the pneumatic c linder and the hydraulic cylinder longitudinally with relation to each other will cause the incompressible iiuid to act upon the piston rod and piston to produce proportional movement of the piston cylinder whereby the energy incident to the relative movement of the pneumatic cylinder and the hydraulic cylinder will be dissipated.

4. A shock absorbing device for aeroplane landing gears comprising a pneumatic cylinder, a piston reciprocable therein, a cylindrical extension carried by the piston and projectin from the mouth of vthe neumatic c lin er, a hydraulic cylinder fitting within t e cylindrical extension and being free to telescope with relation theretosaid cylinder enclosing an incompressible fluid, a piston rod secured to the piston and extendin longitudinally into the hydraulic cylin er, a piston head carried at the end of said rod and at all times submerged in the incompressible fluid, and byass openings through the head to accommo ate the incompressible fluid whereby force tending to move the pneumatic cylinder and the hydraulic cylinder lon tudinally with relation to each other will cause the incompressible fluid to act upon the piston rodand piston to produce proporhead within the pneumatic iis tional movement of the piston head within the pneumatic cylinder whereby the ener inci ent lto the relative movement 'of t e pneumatic c linder andthe hydraulic cylinder will be gissipated.

5. In a shock absorbing strut, an air cylinder, a hydraulic cylinder, and an intermediate element comprising two pistons each of which slides in one of said cylinders, the

piston sliding in said hydraulic cylinder being constructed to permit a metered amount of liquid to flow past it., whereby the movement of one of said cylinders toward or away from the other cylinder is transmitted to the latter cylinder in a modified manner through said intermediate element.,

6. In a hydro-pneumatic shock absorbing strut, Ia pneumatic cylinder, a piston therefor movable against pneumatic pressure to absorb shock, a hydraulic cylinder, a second piston movable againstliquid in said hydraulic cylinder, said second piston being constructed to permit a metered amount of liquid to flow ast it for absorbing shock, said two pistons ing rigidly connected together, whereby the movement of one cylinder is communicable through the two pistons to the other cylinder in a modified degree.

RAYMOND L. GRUSS.

clzaiirlcm: or coRREc'rloN.

Potent No. 1,918,697..

July 18, 1933.

RAYMOND L. cRuss. Daoust-:0, whose Administratrix is LAURA E. GRUSS.

lt is lhereby certified that error appears in the printed epecificationoi the above numbered patent requiring correction es follows: Page 3, line 101, claim 3, for "amount" read "around"; end'thet .the said Letters Patent should be reed with this correction therein that the come may confo in thePatent Gffice.

Signed and sealed this 22nd dey o (Sul) i Agost. A. D. 1933.

M. J. Moore.

mmcminimr t mwa.

rm to the record `of the cue 

